JP2003117683A - Composite brazing filler metal, composite material for brazing, and brazed product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new composite brazing filler metal which has excellent heat resistance and corrosion resistance, and has satisfactory fluidity and brazing operability, to provide a composite material for brazing, and to provide a brazed product. SOLUTION: The composite brazing filler metal 1 consists of a stacked body obtained by stacking a nickel layer 2 consisting of a nickel or nickel alloy, and a non-nickel layer 3 consisting of one kind selected from zinc, a zinc alloy, aluminum and an aluminum alloy. Thus, the composite brazing filler metal can exhibit heat resistance and corrosion resistance more excellent than those of the conventional one, can therefore maintain excellent joining strength, and further, has satisfactory fluidity compared with a nickel simple substance, and is made easy to be treated compared with the powdery one, so that its brazing operability remarkably improves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite brazing material suitable for producing a brazing product such as a cooler for an exhaust gas recirculation system or a member for a fuel cell, which is required to have particularly excellent heat resistance and corrosion resistance. The present invention relates to a brazing composite material and a brazing product using the same.

[0002]

2. Description of the Related Art Conventionally, a stainless base clad material has been used as a brazing member constituting a heat exchanger such as an oil cooler for an automobile. This is one in which one or both sides of a stainless steel plate that is the base material is clad with copper as a brazing material, and the brazing material at the joint of the members is heated above its melting point and welded to braze the base materials together. It is designed to be combined with each other.

As a brazing material for members made of stainless steel, Ni-based or Co-based alloys, various Ni brazing materials having excellent corrosion resistance at joints are specified by the JIS standard. Further, as this Ni brazing material, powdered Ni is used.
A powdered Ni brazing material obtained by adding 4 to 22% by weight of a metal powder selected from Ni, Cr, or a Ni—Cr alloy to the brazing material has also been proposed (JP 2000-107A).
883).

[0004] Similar to the above-mentioned stainless steel-based clad material, a so-called brazing composite material having a brazing layer made of Ni and Ti on the surface of stainless steel which is a base material has also been proposed (Japanese Patent Laid-Open No. Hei 10 (1999) -242242). 7-299592).

[0005]

By the way, these conventional brazing materials or composite materials for brazing are directly exposed to a high temperature and highly corrosive gas or liquid such as a heat exchanger, for example, an exhaust gas recirculation device (hereinafter referred to as "exhaust gas recirculation device"). EGR (Exhaust Gas Recirculat
It has been found that the following problems occur when it is used for the production of a cooler for a fuel cell (referred to as ion) or a cooler for reforming a fuel cell.

That is, first, since extremely high-temperature gas and highly corrosive exhaust gas flow inside the EGR cooler and the fuel cell reforming cooler, the above-mentioned stainless steel-based clad material is used as a material for the EGR cooler and the like. If it is used, sufficient heat resistance and corrosion resistance cannot be exhibited, so that there arises a problem that the brazing material melts or corrodes during use and the joint strength is significantly reduced.

On the other hand, various Ni as shown in JIS standards
Although the brazing material can exhibit excellent heat resistance and corrosion resistance as compared with the above-mentioned stainless steel-based clad material, since its form is powdery, it is necessary to apply it to each joint at the time of use. Is coming. However, since this brazing work requires a great deal of labor and time, there is a problem that the productivity of the brazed product is remarkably low, resulting in an increase in manufacturing cost.

Further, in the conventional brazing composite material, the fluidity of the brazing layer is not good, as will be described later, so that when the brazing member is applied to a brazing member having a complicated shape. However, there is a problem that a good joint surface and a sufficient joint strength cannot be obtained, and the reliability of the joint is lowered.

Therefore, the present invention has been devised to solve the above-mentioned problems, and its purpose is not only to exhibit excellent heat resistance and corrosion resistance, but also to have good melt flowability,
Another object of the present invention is to provide a novel composite brazing material having good brazing workability, a composite material for brazing, and a brazing product.

[0010]

In order to achieve the above object, a first aspect of the present invention provides a nickel layer made of nickel or a nickel alloy and a zinc, zinc alloy, aluminum or aluminum alloy, as set forth in claim 1. It is a composite brazing material characterized by comprising a laminated body in which a non-nickel layer made of any one of them is laminated.

That is, since the conventional nickel metal simple substance has a high melting point of about 1450 ° C., it was difficult to use it as a brazing material for joining stainless steel or the like as it is. However, by lowering the melting point of nickel by combining zinc, aluminum, or both elements, for example, 1
Finding that brazing at around 200 ° C is possible,
The present invention has been achieved. And, in the composite brazing material of the present invention, excellent heat resistance and corrosion resistance can be exhibited as compared with conventional brazing materials such as copper, so that it is of course possible to maintain excellent bonding strength over a long period of time, and nickel alone is used. In comparison, the flowability of the brazing filler metal is good, and handling is easier than in the powder form, so that the brazing workability can be greatly improved.

When the non-nickel layer is further formed with a zinc layer made of zinc or a zinc alloy and an aluminum layer made of aluminum or an aluminum alloy, excellent heat resistance and corrosion resistance can be maintained. In addition, the flowability of the wax can be further improved. Furthermore, as described in claim 3, if the nickel layer further contains 0.02 to 10% by weight of phosphorus to form a nickel-phosphorus alloy, the flowability and wettability of the molten metal can be remarkably improved. It will be possible.

The second invention is a composite material for brazing in which the surface of a base material is clad with the composite brazing material in advance as described in claims 4 and 5, whereby the conventional copper brazing is carried out. Not only can it exhibit excellent heat resistance and corrosion resistance as compared with the composite material for processing, but also the flowability of the molten metal can be greatly improved and excellent brazing workability can be exhibited as compared with the composite material for brazing only nickel.

Also, in the brazing composite material of the present invention, as described in claim 6, the nickel layer of the brazing layer contains 0.02 to 10% by weight of phosphorus and nickel-phosphorus. When alloyed, it becomes possible to remarkably improve the flowability, wettability, etc. of the brazing layer.

Further, since the brazing layer is well compatible with iron and stainless steel, as shown in claims 7 and 8, an alloy containing iron as a main component or stainless steel is used as it is as a base material. It can be used, and the increase in cost of the entire brazing composite material can be suppressed.

Further, as described in claims 9 and 10, by using the novel composite brazing material or the composite material for brazing as described above, highly reliable brazing having excellent heat resistance and corrosion resistance is provided. It is possible to provide products efficiently and at low cost.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

First, FIG. 1 shows an embodiment of a composite brazing material 1 according to the present invention. As shown in the figure, this composite brazing material 1 is a plate-like laminated structure in which a nickel layer 2 made of nickel or a nickel alloy and a non-nickel layer 3 made of any one of zinc, zinc alloy, aluminum or aluminum alloy are superposed. Formed from the body.

Here, this laminate has, for example, a thickness of 0. A few meters
A strip of nickel or a nickel alloy having a strip shape of m and a strip of zinc, a zinc alloy, aluminum or an aluminum alloy, which are also strips, are stacked and repeatedly rolled to obtain a desired thickness easily. The lamination ratio (thickness) of the nickel layer 2 and the non-nickel layer 3 is not particularly limited, and the desired melting point temperature (brazing temperature and heat resistant temperature) can be obtained by arbitrarily changing the ratio. be able to. That is, since the melting point of nickel or nickel alloy forming the nickel layer 2 is higher than that of zinc, zinc alloy, aluminum or aluminum alloy forming the non-nickel layer 3, if the lamination ratio of the nickel layer 2 is increased, the melting point is higher. On the contrary, if the lamination ratio of the non-nickel layer 3 is increased, the melting point can be lowered.
For example, in such a form, the lamination ratio of both is about 1:
When it is 1, the melting point temperature is about 1200 ° C., and the heat resistance and brazing temperature (melt flow) in the vicinity thereof can be exhibited.

Therefore, the brazing filler metal for producing the heat exchanger, for example, the EGR cooler or the fuel cell reforming cooler, which is exposed to the high temperature and highly corrosive gas or liquid described above, is used as the brazing filler metal of the present invention. Since it can exhibit excellent heat resistance and corrosion resistance, it can maintain excellent bond strength over a long period of time, and has better molten metal flowability than the brazing filler metal containing nickel alone Since it is easier to handle, the workability of brazing can be greatly improved.

As another embodiment of the present invention, FIG.
This non-nickel layer 3 with two additional layers,
That is, if the zinc layer 3a made of zinc or a zinc alloy and the aluminum layer 3b made of aluminum or an aluminum alloy are formed, the flowability of the brazing filler metal can be further improved, as shown in Examples described later. Alternatively, as shown in FIG. 3, the nickel layer 2 may be formed into a wire and the periphery thereof may be covered with the non-nickel layer 3 (3a, 3b) to have a circular cross-section. In addition, this nickel layer 2
When phosphorus is contained in the content of 0.02 to 10% by weight, it becomes possible to remarkably improve the flowability and wettability of the molten metal. Here, the phosphorus content is limited to 0.02 to 10% by weight,
This is because if it is less than 0.02% by weight, no improvement in the flowability of the molten metal can be expected, and if it exceeds 10% by weight, the brazing layer becomes brittle and the vibration fatigue characteristics and the bonding strength are significantly reduced.
Desirably, it is in the range of 0.5 to 8% by weight.

Next, FIG. 4 shows an embodiment of the brazing composite material 4 according to the second invention.

As shown in the figure, the brazing composite material 4 has a brazing layer 6 clad on one side of a base material 5 which is a metal component constituting a brazing product such as a heat exchanger, and the brazing material 6 The attachment layer 6 is a nickel layer 2 and a non-nickel layer 3
It is formed by stacking.

Here, the nickel layer 2 is the composite brazing material 1 described above.
Formed from nickel or nickel alloys,
The non-nickel layer 3 is formed of zinc, a zinc alloy, aluminum, or an aluminum alloy.

The brazing layer 6 can be easily formed to a desired thickness by rolling, and can exhibit the same characteristics as the composite brazing material 1, that is, excellent heat resistance and corrosion resistance. If it is used as a member for a heat exchanger that is exposed to the gas or liquid, it is possible to maintain excellent bond strength for a long period of time. Similarly, the brazing layer 6 has better flowability of molten metal than nickel alone,
Moreover, since it is clad integrally with the base material 5 in advance, further excellent workability can be exhibited.

Also in this embodiment, the non-nickel layer 3 of the brazing layer 6 is further provided with two layers, that is, a zinc layer 3a made of zinc or a zinc alloy, as shown in FIG.
And an aluminum layer 3b made of aluminum or an aluminum alloy, the same effect as described above can be obtained. Depending on the part to be used, the brazing layer 6 may be rolled not only on one side as shown in FIG. 6 but also on both sides to be clad, and the base material 5 may be rod-shaped as shown in FIG. If the surface has a complicated three-dimensional shape, the brazing layer 6 can be easily formed on the surface by adopting the plating method instead of the rolling method.

Further, the nickel layer 2 of the brazing layer 6 is further added.
When phosphorus is contained in the amount of 0.02 to 10% by weight, it becomes possible to further remarkably improve the hot water flowability, the wettability and the like of the brazing layer 6 as in the above embodiment.

[0028]

EXAMPLES Specific examples of the present invention will be described below together with comparative examples and conventional examples.

Example 1 First, zinc strips (thickness 0.11)
mm) and nickel strips (thickness 0.10 mm) were clad and laminated by a rolling method, and then rolled repeatedly to produce a composite brazing material having a thickness of 70 μm. Then, this composite brazing material is applied to a stainless steel strip (SUS30) having a thickness of 0.6 mm.
4) Place it so that its zinc side is in contact with it, 1200 ℃
After heating and melting in a vacuum furnace of No. 3 to make a composite, the properties of the composite were evaluated.

As shown in Table 1 below, the evaluation method was performed from the viewpoints of the flowability of the brazing material (fillet forming state), the presence or absence of corrosion, and the brazing productivity. Regarding the flowability of molten metal, S was added to the surface of each composite material produced.
A US304 pipe was placed on the pipe, and the fillet shape of the brazed portion when brazing at 1200 ° C. was evaluated. In addition, the corrosion was evaluated by immersing the sample in a corrosive solution containing chloride ion, nitrate ion, and sulfate ion for 1000 hours, and observing the structure of the brazed part after taking out the sample to examine the presence or absence of corrosion. .

(Example 2) 304 SUS (thickness: 2.0)
mm) and zinc strips (thickness 0.11 m
m), nickel strips (thickness 0.10 mm) are clad by a rolling method, and further rolling is repeated to make the total thickness of zinc and nickel 70 μm, and then heated and melted in a vacuum furnace at 1200 ° C. to form a composite. Then, the characteristics were evaluated by the same method as in Example 1.

(Example 3) The same method as in Example 1 except that an aluminum strip having a thickness of 0.20 mm was used in place of the zinc strip of Example 1, and the thickness of the nickel strip was 0.05 mm. A composite material was produced by the method and the characteristics of the composite material were evaluated.

Example 4 Example 2 The same method as in Example 2 was repeated except that an aluminum strip having a thickness of 0.20 mm was used in place of the zinc strip and the nickel strip had a thickness of 0.05 mm. A composite material was prepared and the properties of the composite material were evaluated.

(Embodiment 5) In addition to the zinc strip and nickel strip of Example 1, an aluminum strip (thickness 0.1 mm) is used, and the thickness of each zinc strip and nickel strip is 0.05 m.
m, 0.10 mm and these zinc, nickel,
Example 1 except that the total thickness of aluminum was 70 μm
A composite material was formed by the same method as described above, and the properties of the composite material were evaluated.

(Example 6) In addition to the zinc strip and the nickel strip of Example 2, an aluminum strip (thickness 0.10 mm) is used, and the thickness of the zinc strip and the nickel strip are each 0.05 m.
m, 0.05 mm and these zinc, nickel,
Example 2 except that the total thickness of aluminum was 70 μm
A composite material was formed by the same method as described above, and the properties of the composite material were evaluated.

(Comparative Example 1) 304 SUS strips (thickness: 2.5)
mm) was directly clad with a nickel strip (thickness 0.15 mm) by a rolling method, the final rolling was performed in the same manner as in Example 2, and then the same evaluation as in Example 1 was performed.

(Conventional Example 1) A similar composite material was formed except that copper strips were used instead of the zinc strips and nickel strips of Example 2,
The characteristics were evaluated in the same manner as in Example 1.

(Conventional Example 2) A commercially available powdered Ni brazing material dissolved in a synthetic resin binder was applied to one side of a SUS304 strip to form a brazing layer, which was then heated at 1200 ° C. in a vacuum furnace.
The wax layer was heated to 100 ° C. for melting and the properties thereof were evaluated in the same manner as in Example 1.

[0039]

[Table 1]

As a result, as is clear from Table 1, Examples 1 to 6 according to the present invention can be brazed at 1200 ° C., and have excellent braze flowability and brazing productivity. In addition, it exhibited excellent corrosion resistance with almost no corrosion. In particular, it was found that in Examples 5 and 6 in which zinc and aluminum were compounded in addition to nickel, extremely good flowability of the molten metal could be exhibited.

On the other hand, in Comparative Example 1, 120
It did not melt at a brazing temperature of 0 ° C. and did not function as a brazing material. Further, Conventional Example 1, which has been conventionally used as a heat exchanger for an oil cooler for automobiles, is good in terms of the flowability of brazing filler metal and the productivity of brazing, but corrosion is caused, resulting in corrosion resistance. Was scarce. Further, the conventional example 2 using the powdery brazing filler metal was good in terms of the flowability of the brazing filler metal and the corrosion resistance, but was inferior to each of the above examples in the brazing productivity.

[0042]

In summary, according to the present invention, excellent heat resistance and corrosion resistance can be exhibited as compared with conventional brazing filler metals such as copper, so that excellent bond strength can be maintained for a long period of time, and nickel alone can be used. In comparison, the flowability of the molten metal is good, and the handling is easier than that of the powdery one, so that the brazing workability is greatly improved. As a result, the production efficiency of the brazed product is improved, and the manufacturing cost can be reduced, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing an embodiment of a composite brazing material according to the present invention.

FIG. 2 is an enlarged sectional view showing another embodiment of the composite brazing material according to the present invention.

FIG. 3A is an enlarged sectional view showing another embodiment of the composite brazing material according to the present invention. (B) is an enlarged sectional view showing a modified example of (a).

FIG. 4 is an enlarged sectional view showing an embodiment of a brazing composite material according to the present invention.

FIG. 5 is an enlarged cross-sectional view showing another embodiment for brazing according to the present invention.

6A is an enlarged cross-sectional view showing another embodiment for brazing according to the present invention, and FIG. 6B is an enlarged cross-sectional view showing a modified example thereof.

FIG. 7 (a) is an enlarged cross-sectional view showing an embodiment for brazing according to the present invention having a circular cross section, and FIG.
[FIG. 11] is an enlarged cross-sectional view showing a modification thereof.

[Explanation of symbols]

1 Composite brazing material 2 Nickel layer 3 Non-nickel layer 3a zinc layer 3b aluminum layer 4 Composite material for brazing 5 base materials 6 Brazing layer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masayoshi Aoyama             1-6-1, Otemachi, Chiyoda-ku, Tokyo             Standing Wire Co., Ltd. (72) Inventor Shirai Kaku             1-6-1, Otemachi, Chiyoda-ku, Tokyo             Standing Wire Co., Ltd.

Claims (10)

[Claims] 1. A composite brazing material comprising a laminated body in which a nickel layer made of nickel or a nickel alloy and a non-nickel layer made of any one of zinc, zinc alloy, aluminum and aluminum alloy are superposed. . 2. A composite brazing material comprising a laminated body in which a nickel layer made of nickel or a nickel alloy, a zinc layer made of zinc or a zinc alloy, and an aluminum layer made of aluminum or an aluminum alloy are superposed on each other. . 3. Phosphorus 0.02-1 in the nickel layer
The content is 0% by weight.
The composite brazing material described in. 4. A brazing composite material in which a brazing layer is clad on the surface of a base material, wherein the brazing layer comprises a nickel layer made of nickel or a nickel alloy, and a zinc, zinc alloy, aluminum or aluminum alloy. A brazing composite material comprising a laminate with a non-nickel layer made of any one of them. 5. In a brazing composite material in which a brazing layer is clad on the surface of a base material, the brazing layer is a nickel layer made of nickel or a nickel alloy, and a zinc layer made of zinc or a zinc alloy. A composite material for brazing, comprising a laminate with an aluminum layer made of aluminum or an aluminum alloy. 6. The brazing composite material according to claim 4, wherein the nickel layer of the brazing layer contains 0.02 to 10% by weight of phosphorus. 7. The brazing composite material according to claim 4, wherein the base material is an alloy containing iron as a main component. 8. The brazing composite material according to claim 4, wherein the base material is stainless steel. 9. A brazed product assembled using the composite brazing material according to any one of claims 1 to 3. 10. A brazed product assembled by the brazing composite material according to any one of claims 4 to 8.